[COMMON] Fix ${!name} bashisms

[COMMON] Fix ${!name} bashisms

pointed out by checkbashisms.

Note this kind of indirections can only be replaced directly in POSIX
by commands using eval.
Security risks must be evaluated for each context where eval is called.
For a safe use, the context must ensure that only a limited number of
possible constrainted values are passed to eval.

https://mywiki.wooledge.org/Bashism#Parameter_Expansions
https://mywiki.wooledge.org/BashFAQ/006#Indirection

Issue-ID: OOM-264
Signed-off-by: Guillaume Lambert <guillaume.lambert@orange.com>
Change-Id: Id27f3ffd1ddb092a9c038d3a45d9e3278720eb62